1. Field of the Invention
In the field of internal combustion engines, the valveless two-stroke engine is desirable from the standpoint of simplicity and relatively high output per unit of weight. Unfortunately, the performance of the conventional two-stroke-c ycle engine suffers from a relatively low volumetric efficiency, caused by the piston uncovering the exhaust port(s) relatively early in the power stroke.
2. Description of the Related Art
U.S. Pat. No. 5,076,220 to Evans et al. discloses a two-stroke-cycle diesel with an offset crankshaft. The engine uses poppet valves in the cylinder head for exhaust.
U.S. Pat. No. 5,074,253 to Dettwiler discloses an oscillating work piston and an oscillating compressor piston. The intake valves are spring-operated. Actually, this is a semi-diesel because it uses a glow plug. The engine has a motion-converting unit.
U.S. Pat. No. 4,884,532 to Tan et al. discloses an oscillating piston two-stroke-cycle engine in which air is admitted at the top and flows to the cylinder through piston grooves. Exhaust ports are located at the end of piston travel. This engine utilizes one connecting rod.
U.S. Pat. No. 4,823,743 to Ansdale discloses a motor-driven compressor using an oscillating vane.
U.S. Pat. No. 4,346,677 to Nye discloses what appears to be a single-acting gasoline engine with an oscillating piston driving a complex set of cranks. It is possible to vary the length of the piston stroke, thereby obtaining a nearly constant compression cycle.
U.S. Pat. No. 4,027,475 to Folsom discloses an engine which may be internal or external combustion, which uses an oscillating rotor, and which uses an energy conversion device to obtain rotary output motion.
U.S. Pat. No. 3,945,348 to Balve discloses a two-vane oscillating engine with a controlled air intake. The location of the intake and exhaust ports is interesting.
U.S. Pat. No. 3,388,693 to James discloses a spark-ignited engine with two power cylinders and one air pump cylinder.
U.S. Pat. No. 3,338,137 to James discloses a spark-ignited engine featuring opposed oscillating pistons. Intake and exhaust ports are in the sides of the combustion chamber.
U.S. Pat. No. 3,318,294 to Harris discloses a spark-ignited two-stroke-cycle engine in which the piston reciprocates. The piston operates an air pressure charger.
U.S. Pat. No. 3,315,648 to Del Castillo discloses an oscillating piston spark-ignited engine, using poppet valves for intake and exhaust. A separate transmission converts oscillating motion into rotary motion.
U.S. Pat. No. 1,490,820 to Gross discloses a four-stroke-cycle spark-ignited engine having two opposed oscillating vanes. The engine uses poppet valves for intake and exhaust.
U.S. Pat. No. 1,010,583 to Carmichael et al. discloses a spark-ignited gasoline engine with two oscillating pistons. There does not appear to be any exhaust means.